RESUMEN
INTRODUCTION: In advanced basal cell carcinoma (BCC), the issue of whether Hedgehog inhibitors (HHIs) should be stopped or not after clinical complete response (cCR) achievement remains an unmet clinical need. MATERIALS AND METHODS: We conducted a retrospective, multicenter study across 7 Italian dermato-oncology units including patients with BCC who continued vismodegib after cCR between 2012 and 2019. We assessed the relationship between the duration of vismodegib intake (days to cCR [DTCR], days to stop after cCR [DTS], total treatment days [TTD]), and disease-free survival (DFS). Reasons to stop vismodegib were (R1) toxicity and (R2) disease recurrence. The relationship between DTCR, DTS, TTD, and DFS in the whole population and in R1 subgroup was assessed by Pearson's correlation coefficient (Pâ <â .05) and Bayesian statistics (BF10). RESULTS: Sixty-eight BCC patients with a median (m) age of 75.5 years (39-100) were included. Most patients were male (Nâ =â 43, 63%), without Gorlin syndrome (Nâ =â 56, 82%) and with head and neck area as primary site (Nâ =â 51, 75%). After cCR, out of 68 patients, 90% (N = 61/68) discontinued vismodegib: 82% (Nâ =â 50/61) due to toxicity (R1), and 18% (Nâ =â 11/61) due to recurrence (R2). Conversely, 10% (Nâ =â 7/68) continued vismodegib until last follow-up. In the whole population (Nâ =â 68), cCR was achieved with a mDTCR of 180.50 days. DFS showed a significant correlation with DTS (Pâ <â .01, BF10â =â 39.2) and TTD (Pâ <â .01, BF10â =â 35566), while it was not correlated to DTCR (BF10â <â 0.1). The analysis of R1 subgroup (Nâ =â 50) confirmed these results. DFS correlated with DTS in all recurrent patients (Nâ =â 38, râ =â 0.44, Pâ <â .01) and in the recurrent patients who stopped vismodegib for toxicity (Nâ =â 26, râ =â 0.665, Pâ <â .01). DFS was longer when vismodegib was maintained for >2 months after cCR (mDFSâ >â 2 months, Nâ =â 54 vs.â ≤â 2 months, Nâ =â 14: 470 vs. 175 d, Pâ <â .01). CONCLUSIONS: Our retrospective results suggest that HHIs should be continued after cCR to improve DFS in BCC.
Asunto(s)
Anilidas , Carcinoma Basocelular , Proteínas Hedgehog , Piridinas , Neoplasias Cutáneas , Humanos , Carcinoma Basocelular/tratamiento farmacológico , Carcinoma Basocelular/patología , Masculino , Femenino , Anciano , Estudios Retrospectivos , Anilidas/uso terapéutico , Anilidas/efectos adversos , Anilidas/administración & dosificación , Persona de Mediana Edad , Anciano de 80 o más Años , Piridinas/uso terapéutico , Piridinas/efectos adversos , Piridinas/administración & dosificación , Proteínas Hedgehog/antagonistas & inhibidores , Adulto , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/patología , Recurrencia Local de Neoplasia/tratamiento farmacológico , Recurrencia Local de Neoplasia/patologíaRESUMEN
Aging is a natural intrinsic process associated with the loss of fibrous tissue, a slower cell turnover, and a reduction in immune system competence. In the skin, the continuous exposition of environmental factors superimposes extrinsic damage, mainly due to ultraviolet radiation causing photoaging. Although not usually considered a pathogenic event, photoaging affects cutaneous biology, increasing the risk of skin carcinogenesis. At the cellular level, aging is typified by the rise of senescence cells a condition characterized by reduced or absent capacity to proliferate and aberrant hyper-secretory activity. Senescence has a double-edged sword in cancer biology given that senescence prevents the uncontrolled proliferation of damaged cells and favors their clearance by paracrine secretion. Nevertheless, the cumulative insults and the poor clearance of injured cells in the elderly increase cancer incidence. However, there are not conclusive data proving that aged skin represents a permissive milieu for tumor onset. On the other hand, tumor cells are capable of activating resident fibroblasts onto a pro-tumorigenic phenotype resembling those of senescent fibroblasts suggesting that aged fibroblasts might facilitate cancer progression. This review discusses changes that occur during aging that can prime neoplasm or increase the aggressiveness of melanoma and non-melanoma skin cancer.
Asunto(s)
Envejecimiento de la Piel , Neoplasias Cutáneas , Anciano , Humanos , Rayos Ultravioleta/efectos adversos , Neoplasias Cutáneas/etiología , Envejecimiento , Piel , CarcinogénesisRESUMEN
INTRODUCTION: Small-sized pigmented lesions (SSPL) <3 mm in diameter are common pitfall in the daily dermatology practice. Dermoscopy alone is hampered by the lack of specific features inversely proportional to the diameter of the lesions and its performance is highly operator-dependent. Reflectance confocal microscopy (RCM) has been demonstrated to be effective in the diagnosis of several difficult lesions where dermoscopy lacks to provide conclusive information. MATERIALS AND METHODS: A total of 179 lesions with uncertain or equivocal clinical and dermoscopy appearance were selected. Dermoscopist has been requested to express a diagnostic suspect when possible. Equivocal lesions underwent RCM performed by expert for second-level evaluation before surgical excision for histological diagnosis. Results have been later statistically analysed. RESULTS: Dermoscopy was not diagnostic in large number of lesions with low concordance histology (39.1%) instead of a much high concordance when combined with RCM (93.9%). CONCLUSIONS: Small-sized pigmented lesions were more likely to be located on the face area. Diagnosis of pigmented BCC was relatively easy on dermoscopy and also in the case of small lesions showing typical signs of BCC. LM and MM have been seen to be particularly difficult to be diagnosed using only dermoscopy. The combination of digital dermoscopy and RCM represents the correct approach of SSPL.
Asunto(s)
Dermoscopía , Microscopía Confocal , Neoplasias Cutáneas , Cara , Humanos , Neoplasias Cutáneas/diagnóstico por imagen , Pigmentación de la PielRESUMEN
Nevoid basal cell carcinoma syndrome (NBCCS), also named Gorlin syndrome, is a rare multisystem genetic disorder characterized by marked predisposition to basal cell carcinomas (BCCs), childhood medulloblastomas, maxillary keratocysts, celebral calcifications, in addition to various skeletal and soft tissue developmental abnormalities. Mutations in the tumor suppressor gene PATCHED1 (PTCH1) have been found to be associated in the majority of NBCCS cases. PATCH1 somatic mutations and loss of heterozygosity are also very frequent in sporadic BCCs. Unlike non-syndromic patients, NBCCS patients develop multiple BCCs in sun-protected skin area starting from early adulthood. Recent studies suggest that dermo/epidermal interaction could be implicated in BCC predisposition. According to this idea, NBCCS fibroblasts, sharing with keratinocytes the same PTCH1 germline mutation and consequent constitutive activation of the Hh pathway, display features of carcinoma-associated fibroblasts (CAF). This phenotypic traits include the overexpression of growth factors, specific microRNAs profile, modification of extracellular matrix and basement membrane composition, increased cytokines and pro-angiogenic factors secretion, and a complex alteration of the Wnt/-catenin pathway. Here, we review studies about the involvement of dermal fibroblasts in BCC predisposition of Gorlin syndrome patients. Further, we matched the emerged NBCCS fibroblast profile to those of CAF to compare the impact of cell autonomous "pre-activated state" due to PTCH1 mutations to those of skin tumor stroma.
Asunto(s)
Síndrome del Nevo Basocelular/patología , Carcinoma Basocelular/patología , Fibroblastos/patología , Neoplasias Cutáneas/patología , Animales , Síndrome del Nevo Basocelular/metabolismo , Carcinoma Basocelular/metabolismo , Fibroblastos/metabolismo , Humanos , Receptor Patched-1/metabolismo , Transducción de Señal/fisiología , Neoplasias Cutáneas/metabolismoRESUMEN
BACKGROUND: Cutaneous malignant melanoma (CMM) is one of the most common skin cancers worldwide. CMM pathogenesis involves genetic and environmental factors. Recent studies have led to the identification of new genes involved in CMM susceptibility: beyond CDKN2A and CDK4, BAP1, POT1, and MITF were recently identified as potential high-risk melanoma susceptibility genes. OBJECTIVE: This study is aimed to evaluate the genetic predisposition to CMM in patients from central Italy. METHODS: From 1998 to 2017, genetic testing was performed in 888 cases with multiple primary melanoma and/or familial melanoma. Genetic analyses included the sequencing CDKN2A, CDK4, BAP1, POT1, and MITF in 202 cases, and of only CDKN2A and CDK4 codon 24 in 686 patients. By the evaluation of the personal and familial history, patients were divided in two clinical categories: "low significance" and "high significance" cases. RESULTS: 128 patients (72% belonging to the "high significance" category, 28% belonging to the "low significance" category) were found to carry a DNA change defined as pathogenic, likely pathogenic, variant of unknown significance (VUS)-favoring pathogenic or VUS. CONCLUSIONS: It is important to verify the genetic predisposition in CMM patients for an early diagnosis of further melanomas and/or other tumors associated with the characterized genotype.
Asunto(s)
Predisposición Genética a la Enfermedad/genética , Melanoma/genética , Melanoma/metabolismo , Adulto , Anciano , Quinasa 4 Dependiente de la Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Femenino , Humanos , Italia , Masculino , Factor de Transcripción Asociado a Microftalmía/genética , Persona de Mediana Edad , Estudios Retrospectivos , Complejo Shelterina , Proteínas de Unión a Telómeros/genética , Proteínas Supresoras de Tumor/genética , Ubiquitina Tiolesterasa/genéticaAsunto(s)
Carcinoma de Células Escamosas , Neoplasias Cutáneas , Humanos , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/patología , Radioterapia Adyuvante , Neoplasias Cutáneas/radioterapia , Neoplasias Cutáneas/patología , Técnica Delphi , Estudios Retrospectivos , Márgenes de Escisión , Recurrencia Local de Neoplasia/patología , Estadificación de NeoplasiasRESUMEN
BACKGROUND/OBJECTIVES: The clinical and dermoscopic differential diagnosis of flat pigmented facial lesions represents a great challenge for the clinicians. Our aim was to report a quantitative method based on dermoscopic features to better classify pigmented facial lesions. METHODS: This is a retrospective case-series study that analysed the dermoscopic features of 582 pigmented facial lesions. RESULTS: The individual patient probability of lentigo maligna (LM) was predicted by a multivariate model, with an accuracy of 0.72. According to the odds ratio at the multivariate analysis, an individual scoring index was assigned to each criterion, and a value of 4.56 was identified as optimal cut-off point. Up to a score of 2.5, the probability that a lesion is an LM is 0. The probability increases from 10 to 50% for a score ranging between 4.5 and 6. It is about 90% for a score of 7. CONCLUSION: The optimal cut-off point obtained and the curve that identifies the probability of a patient having a LM could improve the classification and the management strategies of equivocal pigmented facial lesions.
Asunto(s)
Neoplasias Faciales/diagnóstico por imagen , Peca Melanótica de Hutchinson/diagnóstico por imagen , Neoplasias Cutáneas/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Dermoscopía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Probabilidad , Estudios Retrospectivos , Medición de Riesgo/métodos , Adulto JovenRESUMEN
BACKGROUND: Little is known about the dermoscopic features of keratinocyte skin cancer. OBJECTIVE: We sought to determine the dermoscopic features of facial actinic keratosis (AK), intraepidermal carcinoma (IEC), moderately to poorly differentiated invasive squamous cell carcinoma (SCC), and well-differentiated SCC of the keratoacanthoma type. METHODS: This was a retrospective analysis of dermoscopic images of histopathologically diagnosed keratinocyte skin cancer. RESULTS: A total of 243 (70 AK, 71 IEC, 78 SCC, and 24 keratoacanthomas) tumors of the face from 243 patients (mean age: 71.1 years; range: 44-94 years) were analyzed. The majority of patients had a fair skin type, history of melanoma or nonmelanoma skin cancer, and multiple AK. A red pseudonetwork was significantly associated with AK (P < .001), whereas dotted/glomerular vessels, diffuse yellow opaque scales, and microerosions were significantly more prevalent among IEC (P < .001). Hairpin vessels, linear-irregular vessels, targetoid hair follicles, white structureless areas, a central mass of keratin, and ulceration were significantly associated with invasive SCC (P < .001 for all criteria). Similar patterns as in SCC were observed among keratoacanthomas. LIMITATIONS: The retrospective design of our study and the lack of assessment of sensitivity and specificity of the dermoscopic criteria are limitations. CONCLUSIONS: Based on our findings we propose a progression model of facial AK developing into IEC and invasive SCC.
Asunto(s)
Carcinoma de Células Escamosas/patología , Dermoscopía , Dermatosis Facial/patología , Queratoacantoma/patología , Queratosis Actínica/patología , Neoplasias Cutáneas/patología , Adulto , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Invasividad Neoplásica , Estudios RetrospectivosRESUMEN
BACKGROUND: The dermoscopic patterns of pigmented skin tumors are influenced by the body site. OBJECTIVE: To evaluate the clinical and dermoscopic features associated with pigmented vulvar lesions. METHODS: Retrospective analysis of clinical and dermoscopic images of vulvar lesions. The χ² test was used to test the association between clinical data and histopathological diagnosis. RESULTS: A total of 42 (32.8%) melanocytic and 86 (67.2%) nonmelanocytic vulvar lesions were analyzed. Nevi significantly prevailed in younger women compared with melanomas and melanosis and exhibited most commonly a globular/cobblestone (51.3%) and a mixed (21.6%) pattern. Dermoscopically all melanomas showed a multicomponent pattern. Melanotic macules showed clinical overlapping features with melanoma, but their dermoscopic patterns differed significantly from those observed in melanomas. CONCLUSION: The diagnosis and management of pigmented vulvar lesions should be based on a good clinicodermoscopic correlation. Dermoscopy may be helpful in the differentiation of solitary melanotic macules from early melanoma.
Asunto(s)
Dermoscopía , Melanoma/patología , Nevo Pigmentado/patología , Neoplasias Cutáneas/patología , Neoplasias de la Vulva/patología , Adolescente , Adulto , Femenino , Humanos , Melanosis/patología , Persona de Mediana Edad , Vulva/patología , Adulto JovenRESUMEN
Activating mutations in the Hh pathway underlies the development of sporadic and familial skin BCC. For these oncogenic proliferations displaying ligand-independent activation of the intracellular pathway, two molecules have been approved for therapeutic purposes: vismodegib and sonidegib. Improper Hh signalling occurs in many human tumours also via a paracrine mechanism (ligand-dependent) in which the secretion of Hh ligands by stromal cells support tumour growth. On the other hand, the mobilization of neoplastic stroma by cancer cells is sustained by the activation of Hh signalling in surrounding fibroblasts suggesting a central role of this bidirectional crosstalk in carcinogenesis. Additionally, loss-of-function mutations in the PTCH1 gene in the context of NBCCS, an autosomal dominant disorder predisposing to multiple BCCs, determine tumour permissive phenotypes in dermal fibroblasts. Here, profiling syndromic and BCC-associated fibroblasts unveiled an extraordinary similarity characterized by overexpression of several Hh target genes and a marked pro-inflammatory outline. Both cell types exposed to Hh inhibitors displayed reversion of the tumour-prone phenotype. Under vismodegib and sonidegib treatment, the Wnt/ß-catenin pathway, frequently over-active in tumour stroma, resulted down-regulated by pAKT-GSK3ß axis and consequent increase of ß-catenin turnover. Overall, this study demonstrated that vismodegib and sonidegib impacting on fibroblast tumour supportive functions might be considered in therapy for BCC independently to the mutation status of Hh components in neoplastic cells.
RESUMEN
BACKGROUND: Enlarging melanocytic lesions with peripheral globular pattern (EMLPGP) are a pitfall in dermoscopy. Our aim was to evaluate the meaning of EMLPGP and to assess the use of dermoscopy and reflectance confocal microscopy (RCM) in order to improve the clinical management of this subtype of melanocytic lesions. METHODS: A total of 135 EMLPGP were recruited and, accordingly to the dermoscopy features, were removed; later, an expert dermoscopist reviewed the lesions blinded to histology. Moreover, a subgroup of 63 lesions who underwent also to RCM, were reviewed by an expert confocalist. RESULTS: Patients had a median age of 41 years old and a female prevalence (61.5%). The main anatomic site was the trunk (86%). Histology of the 135 excised EMLPGP disclosed 116 nevi (86%; P<0.0001) and 19 melanomas (14%). On dermoscopy, statistical significance was detected for small globules that were observed in 106 cases (78.5%; P<0.0001), while globules distribution and color did not impact the diagnosis prediction, as well as age, sex or any other patient profile. Considering the RCM, atypical cytology and irregular architecture were detected in 100% of melanomas (P<0.0001). CONCLUSIONS: Our study shows that EMLPGPs are detectable in every age and can be a pitfall in especially in high risk patients with an over-excision of lesions. The presence of peripheral globules should be evaluated considering the overall dermoscopic features. RCM can contribute significantly in the management of lesions trough the detection of cyto-architectural atypia. Therefore, RCM in combination with dermoscopy can optimize the reduction of harmless lesions.
Asunto(s)
Melanoma , Neoplasias Cutáneas , Adulto , Dermoscopía , Femenino , Humanos , Melanocitos , Melanoma/diagnóstico por imagen , Microscopía Confocal , Neoplasias Cutáneas/diagnóstico por imagenRESUMEN
This corrects the article DOI: 10.23736/S0392-0488.18.06082-0.
RESUMEN
BACKGROUND: Actinic keratosis (AK) is a photo-induced skin lesion. It has been considered by several authors as in-situ squamous cell carcinoma (SCC), that can evolve to invasive SCC (iSCC). Given the malignant potential and because it is impossible predict which AK will evolve in iSCC, it is necessary to treat each lesion. Multiple therapeutic approaches have been described to treat AKs. In addition to the topical drugs, photodynamic therapy (PDT) has become an established therapeutic modality for grade I and II of AKs of face and scalp. Recently the daylight photo-dynamic therapy (DL-PDT) has found extensive use in the care of the AK and in the field cancerization. METHODS: The study included 101 patients, 90 males and 11 females, mean age 71, phototype I-II, with multiple AK I and II of the face and the scalp, treated with DL-PDT. Patients were clinically evaluated for 3 months. The aim of this study was to show our experience in Daylight Photodynamic Therapy, to confirm the validity in term of efficacy and safety of DL-PDT for I and II AK of face and scalp and to underline the patient's higher satisfaction for this type of treatment and his availability to be retreated with the DL-PDT. RESULTS: The efficacy was complete in 16 patients (15.8%), in 71 patients (70.3%) was much improved or improved and only in 14 (13.9%) subjects were minimal, while nobody had worsened or changed. The majority of patients (84.2%) patients were satisfied of the efficacy as well of the cosmetic results, only 15 (14.9%) were low satisfied and one patient was not satisfied. CONCLUSIONS: This study confirms that the DL-PDT is a good alternative to c-PDT for the treatment of grade I and II AK of the face and scalp and in Rome, as in Southern Europe, it is possible to perform the DL-PDT in almost every month of year.
Asunto(s)
Queratosis Actínica/tratamiento farmacológico , Fotoquimioterapia/métodos , Luz Solar , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Cara , Femenino , Humanos , Queratosis Actínica/patología , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Fotoquimioterapia/efectos adversos , Estudios Retrospectivos , Ciudad de Roma , Cuero Cabelludo , Resultado del TratamientoRESUMEN
: In the cART era, the incidence of AIDS-defining cancers decreased, whereas a persistence of non-AIDS-defining cancers has been observed. In particular, concerning the risk of melanoma and nonmelanoma skin cancers in HIV patients, conflicting data are available. In this study, our aim was to assess the occurrence of cutaneous malignancies in 97 HIV-positive individuals visited in our Institute, and to evaluate the association with immunological parameters, as well as combination antiretroviral therapy (cART) duration.
Asunto(s)
Infecciones por VIH , Melanoma , Neoplasias Cutáneas , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , VIH-1 , Humanos , Incidencia , Masculino , Melanoma/epidemiología , Persona de Mediana Edad , Neoplasias Cutáneas/epidemiologíaRESUMEN
Lichen sclerosus (LS) is a chronic inflammatory skin condition usually located in the anogenital area. Topical corticosteroid therapy is the first choice treatment which may arrest or delay the progression of the disorder. We report the case of a 74-year-old man presented with a 6-month history of nodular lesions localized on penis. The man had a previous history of genital lesions that had been diagnosed as LS and treated with long-term topical corticosteroid therapy. After 3 months of corticosteroid therapy, the patient observed the appearance of several nodular erythematous lesions on the penis with progressive disappearance of the clinical symptoms of LS. These purple to red asymptomatic angiomatoid nodules resembled the clinical features of Kaposi sarcoma.
Asunto(s)
Glucocorticoides/efectos adversos , Liquen Escleroso y Atrófico/tratamiento farmacológico , Enfermedades del Pene/inducido químicamente , Anciano , Clobetasol/efectos adversos , Clobetasol/análogos & derivados , Clobetasol/uso terapéutico , Glucocorticoides/uso terapéutico , Humanos , Liquen Escleroso y Atrófico/patología , Masculino , Enfermedades del Pene/tratamiento farmacológico , Enfermedades del Pene/patología , Pene/patología , Sarcoma de Kaposi/diagnóstico , Sarcoma de Kaposi/patologíaRESUMEN
Despite its low incidence, vulvar melanoma carries a poor prognosis and shows a high tendency to metastasize because the diagnosis is often delayed. Although it is very well known that ultraviolet radiation is an important aetiological factor for cutaneous melanomas in adults, this cannot be considered true for vulvar melanoma. Chronic inflammatory disease, viral infections, irritant agents are the main factors suspected to induce mucosal melanoma. We report 10 cases of vulvar malignant melanoma observed in our institute from 1990 to 2005 and a review of the literature.
Asunto(s)
Melanoma/patología , Neoplasias de la Vulva/patología , Adolescente , Anciano , Femenino , Humanos , Metástasis Linfática/patología , Melanoma/cirugía , Persona de Mediana Edad , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/cirugía , Vulva/patología , Neoplasias de la Vulva/cirugíaRESUMEN
Basal cell carcinoma (BCC) is the most common cancer affecting Caucasians and, due to its large size or to the poor condition of the patient, it can be difficult to treat it with conventional therapies: in these cases photodynamic therapy with methyl aminolevulinate (MAL-PDT) may represent a good option. A retrospective non-comparative follow-up study was performed to test the response of giant and large BCC to MAL-PDT. Twelve patients with 14 giant BCC (> or = 5 cm) and 5 patients with 5 large BCC (4-5 cm) were treated with MAL-PDT; they were evaluated 6 months after the end of the treatment to define the initial cure rate, and then at 12 and 36 months for the follow-up. At 6 months the initial cure rate for the 19 BCCs was 95% and at 36 months the overall long-term cure rate was 66%. The follow-up will last up to 5 years. MAL-PDT is a valid option for the treatment of giant and large BCC.
Asunto(s)
Ácido Aminolevulínico/análogos & derivados , Carcinoma Basocelular/tratamiento farmacológico , Fotoquimioterapia , Fármacos Fotosensibilizantes/administración & dosificación , Neoplasias Cutáneas/tratamiento farmacológico , Administración Tópica , Anciano , Anciano de 80 o más Años , Ácido Aminolevulínico/administración & dosificación , Carcinoma Basocelular/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Cutáneas/patologíaAsunto(s)
Queratosis/diagnóstico , Erupciones Liquenoides/diagnóstico , Melanoma/diagnóstico , Neoplasias Cutáneas/diagnóstico , Anciano , Dermoscopía , Diagnóstico Diferencial , Humanos , Masculino , Melanocitos/patología , Melanoma/patología , Microscopía Confocal , Piel/patología , Neoplasias Cutáneas/patologíaRESUMEN
The ultimate outcome of an immune response (escape or surveillance) depends on a delicate balance of opposing signals delivered by activating and inhibitory immune receptors expressed by cytotoxic T lymphocytes and natural killer cells. In this light, loss and down-regulation of human leukocyte antigens (HLA) class I molecules, while important for keeping tumors below the T-cell detection levels, may incite recognition of missing self. Conversely, the maintenance of normal levels of expression (or even up-regulation) may be favorable to tumors, at least in certain cases. In this study, we took advantage of a previously characterized panel of 15 early passage tumor cell lines (mainly from melanoma and lung carcinoma lesions) enriched with class I-low phenotypes. These cells were systematically characterized by Northern and/or Western blotting (e.g., mini-transcriptome/mini-proteome analysis) for the expression of HLA-A, -B, -C, beta(2)-microglobulin, and the members of the "antigen processing machinery" of class I molecules (LMP2, LMP7, TAP1, TAP2, tapasin, calreticulin, calnexin, and ERp57). In addition, we established four pairs of cultures, each comprising melanoma cells and normal melanocytes from the same patient. We found that approximately 97% of the 185 tested gene products are expressed (although often weakly), and in many cases coordinately regulated in 18 of 19 tumor cell lines. Linked expression patterns could be hierarchically arranged by statistical methods and graphically described as a class I HLA "coordinome." Deviations (both down- and up-regulation) from the coordinome expression pattern inherited from the normal, paired melanocyte counterpart, were allowed but limited in magnitude, as if melanoma cells were trying to keep a "low profile" HLA phenotype. We conclude that irreversible HLA loss is a rare event, and class I expression in tumor cells almost invariably results from reversible gene regulatory (rather than gene disruption) events.